The system has the potential to provide important services for balancing energy supply and demand, helping to support greater integration of intermittent renewable generation, as well as improving power quality and reliability for customers.

‘Battery storage holds tremendous promise in helping electric utilities like PG&E enhance the overall reliability of an ever-changing energy supply,’ said Greg Kiraly , PG&E’s senior vice president of distribution operations. ‘This pilot project will provide critical, real-world data on the technical and financial performance of battery energy storage to help us understand how battery storage devices can serve PG&E’s customers and the overall electric grid.’
The utility operates a similar 2 MW battery system near its Vaca-Dixon solar plant in Solano County, California.

The Yerba Buena project was funded in part by a $3.3 million grant from the California Energy Commission.

PG&E is working in close coordination with the Electric Power Research Institute (EPRI) to study how NaS battery energy storage can improve power quality and reliability, support greater integration of intermittent renewable power, and supply energy to California’s electricity market, overseen by the California Independent System Operator. EPRI’s reports will be made available to the public.

S&C Electric Company is the engineering, procurement and construction contractor for the project and supplied the storage management system and power conversion equipment that control the battery’s AC input/output and its interface with the electric grid. NGK Insulators makes NaS battery systems which include the battery modules and control system for managing DC input/output and other parameters for maximizing module longevity.
Recently NGK Insulators signed a framework agreement with Terna, Italy’s largest transmission system operator (TSO), to supply its NaS energy storage system, which will make it the first large-scale installation of the technology in a European grid system.
According to the framework agreement, maximum quantity equal to 70 MW with seven hours discharge. The first phase order under this agreement is expected with the volume of 35 MW and the contract price of the system is about EUR100 million.

In order to achieve CO2 emissions reduction targets, European nations have agreed to increase the percentage of renewable generation to 20% by 2020. Italy recorded a 72% increase in solar generation and a 34% increase in wind generation during 2012.www.pge.comwww.ngk.co.jp